There is a version of residential design where the client's brief arrives, the plot dimensions arrive, and a plan is drawn that satisfies both. It usually works. It also usually produces a building that could have been put on any plot in the country, and which spends the rest of its life being corrected by air conditioning.
The alternative costs one day. Go to the site, stay a while, and answer a specific set of questions before drawing anything.
Orientation, and the two elevations that matter
Sri Lanka is between roughly 6 and 10 degrees north. The sun passes close to overhead for much of the year and crosses to the north of vertical for part of it. The practical consequence is counter-intuitive to anyone trained on temperate rules of thumb: the hard elevations here are east and west, not south.
A low morning sun on an east wall and a low afternoon sun on a west wall both deliver a lot of energy at an angle that no reasonable overhang will stop. North and south elevations, by contrast, take high-angle sun that a modest projection handles comfortably.
This single fact should shape the plan:
- Put the long axis of the building roughly east–west, so the large elevations face north and south.
- Put the rooms you do not need to keep cool — stores, stairs, utility, garages, service cores — on the east and west ends, where they act as thermal buffers.
- Give west-facing glass a real reason to exist. If there is a view worth taking the afternoon heat for, take it deliberately and shade it with something vertical: fins, louvres, planting. A horizontal overhang will not help you at four in the afternoon.
Wind is more valuable than shade
Shade prevents a room from getting hot. Air movement is what makes a warm room comfortable. In a humid climate the second matters more, and it is the one most often designed away.
Stand on the site and find the prevailing breeze. In much of the wet zone it swings with the monsoon — broadly southwesterly for a large part of the year, northeasterly for another part. You want the plan to let air enter on the windward side and leave on the leeward side, with as few obstructions between the two as possible.
That means, concretely:
- Openings on opposite walls of the same room, not two openings on the same wall.
- Openable area at both low and high level, so warm air can leave at the ceiling while cooler air enters below.
- Internal doors, transoms and openable fanlights that let the cross-breeze pass through the plan rather than stopping at the first partition.
- A stair or double-height space positioned to work as a chimney, pulling air upward and out through a high vent.
What the neighbours have already decided for you
A plot is rarely alone. Before drawing, record:
- The height and position of buildings on all sides, and where their windows look.
- Which of your boundaries will be built up against later, and to what height. Assume the worst permissible case.
- Where the noise comes from — road, temple, school, generator, air-conditioning condensers.
The second point governs more than it seems to. Designing a beautiful courtyard against a boundary that a neighbour is entitled to build a three-storey wall on is designing a light well that will one day be a shaft. Either place the openings where the sky is protected by setback rules, or design the space to work when the wall arrives.
Trees, and the case for keeping them
A mature tree on a site is worth more than almost anything you can build in its place. It shades a roof for free, cools the air passing under it by evaporation, holds the soil, and takes twenty years to replace.
It also has a root zone, and the root zone is a design constraint. As a working assumption, keep foundations, trenches and site huts outside the canopy's drip line. If the plan requires building closer, that is a decision to make consciously with the arborist and the structural engineer, not something to discover when the excavator arrives.
Note also which trees drop what, and when. A tree that fills a gutter every October changes the gutter detail.
Ground, water and the slope
Three things to establish on the first visit, and confirm with proper investigation before design freezes:
Where does surface water currently go? Every site already has a drainage pattern. Find the low point and find the outfall. A building that interrupts an existing overland flow path without replacing it will collect that water somewhere less convenient.
How high does the water table come? Ask the neighbours. Somebody has dug a well, a soakaway or a foundation nearby and knows. A high water table changes the basement conversation from "how much will it cost" to "should we".
What is the fall across the plot, and in which direction? A slope is an opportunity — split levels, a lower ground floor that opens to a garden, natural drainage — but only if the design uses it. A slope that gets levelled is a slope you paid to remove and then paid again to retain.
Setbacks, coverage and the envelope you are actually allowed
Before the first sketch, establish the regulatory envelope: required setbacks from each boundary, permissible site coverage, height limits, and any local authority or Urban Development Authority conditions that apply to the specific zone. These vary by authority and by zone, and they change; confirm them with the relevant authority for the specific plot rather than assuming the last project's numbers carry over.
Draw that envelope as a three-dimensional volume. Everything you design happens inside it. Designing first and testing compliance afterwards is how schemes get redrawn.
The output of a site reading
By the end of the day you should be able to state, in a paragraph and a diagram, where the building sits, which way it faces, where it opens, where it closes, where the water goes and which existing features it keeps. That paragraph is the design. Everything after it is resolution.
